Transcript The Future of Laser Nuclear Physics

Carpathian Summer School, Sinaia, Romania 2012
The Future
of Laser Nuclear Physics
Ken Ledingham
SUPA, Dept of Physics, University of Strathclyde, Glasgow G4
0NG, Scotland & AWE plc Aldermaston, Reading, RG7 4PR,
Over the last 10 years my
group and now the SUPA
group working with Klaus
Spohr have worked on what we
call “Laser Induced Nuclear
Physics”What is this?
What are the Laser Driven
Nuclear Reactions?
• Gamma induced fission
• Gamma and proton cross sections
• Laser produced neutron activation
analysis
• Photon and charged particle production
of radio-active isotopes including PET
isotopes
• Laser production of monoenergetic
protons
VULCAN petawatt laser (RAL)
Energy
600 J (on target)
Repetition
1 hour
Wavelength
1.05 m
Pulse duration
0.6 ps
Intensity
~6x1020 Wcm-2
Maximum pulses
per week
~25
Petawatt with Extensive Nuclear
Shielding
Nuclear beams generated by an intense
laser beam (Ulrich Schramm)
CCD camera
“STRAIGHT THROUGH”
DIRECTION
“BLOW-OFF”
DIRECTION
Protons
Protons
Cu activation
stack
Al
target
Cu activation stack
CPA pulse
Proton spectra using activation techniques
Proton Spectra from 100TW
In front of target
– “blow-off”
direction
5 cm
5 cm
FRONT
5 cm
5 cm
Behind the target –
“straight through”
direction
BACK
Monoenergetic
Protons from
Mass Limited
Targets
Experimental Arrangement
Multi Channel
Plates
Laser Irradiation of DOT Targets
Simulation of the experiment
2D-PIC simulation for following conditions:
IL= 3  1019 W/cm2, 5 µm Ti-foil + 0.5 µm PMMA dot (20  20) µm2
First „Monoenergetic“ Proton Beams
from isolated water droplets
Ti-Sa laser pulse:
forward Protons :
40 fs, 21019 W/cm2,
contrast 10-8
Thomson spectrometer
20 
deuterons ((20 keV sr)
-1
)
drop21053f
1E8
1E7
0.2
0.4
0.6 0.8 1
2
4
energy (MeV)
Important:
laser pulse shape and target structure
Mass Limited Cone
Targets
Kirk Flippo, Tom Cowan et al
Snow Targets
Laser Irradiation of Snow targets
Laser Wakefield
Acceleration of
Electrons
Electron acceleration in a capillary discharge
waveguide
Lawrence Berkeley National Lab:
W. Leemans, B. Nagler, C. Tóth,
K. Nakamura, C. Geddes, E. Esarey,
C. Schroeder
Oxford University:
S. M. Hooker and A. J. Gonsalves
Waveguide:
Guiding of 40 TW laser pulses:
• in capillary discharge waveguide
• over 33 mm of plasma
Input spot
Exit spot
Electron acceleration:
Generation of e-beams with:
• %-level energy spread
• mrad divergence
• Energy up to 1 GeV
Applications of
Laser Driven
Particle Beams
PET Isotope
Production
Laser Beam
Laser driven PET isotope production
1010
109
Activity (Bq)
108
107
106
105
104
103
102
1019
1020
1021
Irradiance (Wcm-2m2)
Activity as a function of laser intensity. The
black and red hatched areas are for typical
patient doses for 18F and 11C
Laser-driven photo129
transmutation of I – a long
lived nuclear waste product
•
129I
has a half-life of 15.7 x 106 years
•
128I
has a half-life of 25 mins
• The transmutation was carried out using
a laser driven (, n) reaction
Nuclear activation: Experiment arrangement
Activation
samples
Iodine
samples
Laser pulse
Resistively
heated target
(,n) reaction in 129I using a Ge detector to
measure decay of 128I
The Generation of Gamma ray
light sources
• First of all you require GeV electron beams
generated by lasers or by conventional
linacs
• Compton backscatter laser photons to
produce multi-MeV gamma ray beams.
IR-electron bunch collision
IR bunch
Electron bunch
First x-rays of collision produced when bunches 1st meet.
A
Last x-rays of collision produced when bunches separate.
A
Z
X-rays A through Z travel at c with electron bunch.
Z
A
Time
s x-rays =
selectrons
Courtesy George Neil, JLab
Peak brilliance of light sources with star of GRLS at 1MeV 15
orders of magnitude greater than all synchrotrons and FELS
Gamma Ray Light
Sources (GRLS)
NUCLEAR Applications
of Intense Gamma Ray
Beams – Nuclear
resonance Fluorescence
GRLS)
Gamma ray resonant
fluorescence
Mainland security
Nuclear waste reclassification
Storing radioactive waste at power stations
There are hundreds of thousands of such barrels
world wide with very little knowledge of the contents.
GRLSs would enable certifiable classification of the
waste contents
Depository of hundreds of drums
of radioactive waste
Nuclear Resonance Fluorescence
Example of NRF spectra obtained
from a plutonium target.


Level Scheme for Pu 239
Nuclear Physics at High
Temperatures
This is a nuclear regime which is best
carried out using lasers - opportunities
at XFEL and ELI Bucharest
At present there is no laser
induced reaction which cannot
be done better using
conventional accelerators –
at high temperatures this
could be very different
What do we intend to do
at high temperatures –
modification of the half
life of 26Al using the high
temps produced by
coincident laser driven
particle beams
How do we make the Al26 -use
the PW short pulse laser to
generate a proton beam and
26
26
then use a Mg (p,n)Al reaction
Simultaneously heating with a
laser produced gamma ray beam
or thus a Mg26(pγ,n)Al26 reaction
Al26 Decay scheme
Motivation
Level scheme
Skelton R et. al., Phys.Rev. C35(1),45,1987
•
26Al
in the astrophysical context
using a gamma camera
•
•
Interstellar abundance
1809 keV line in Galaxy
NASA Compton Gamma Ray observatory (COMPTEL) 1991-2000 & Plüschke S et
al., arXiv:astro-ph/0104047v1
Evolution of stellar abundance
Voss R et al., Astronomy & Astrophysics, 504, 531, 2009
Schematic of laser plasma nuclear 26Al experiment
Use the NIF PW laser at
1022 W/cm2 or VULCAN
Edriver~15J
High temperature production pulse
(hard photon beam)
'p-production
pulse'
TSNA
I~1018-20 Wcm-2
26Mg
p
Shielding
Canvas
Diamond
Target
NaI or Ge
ORGAM Detector System
Laser Induced Fission of 238U and
Nuclear Fission Yields as a Fn of Temp
Al-production target
Proton beam
isochoric heated
volume
depleted 238U
thickness: 8μm
encapsulated by Al-foils
Fission products &
trajectories
Laser
~200μm
Cu-stack
Front Al-sheet 1
thickness: 10μm
isochoric heated
0-40μm
variable
Back Al-sheet 2
thickness:10μm
Al-U-Al sandwich target
This was an experiment to be carried out using short pulse
laser isochoric heating but could be done by NIF heating
Nuclear Excitation in
Plasmas NEET/NEEC
Nuclear Opportunities at
XFEL 2015 and ELI
Thank you for
listening